Issue with Layout Constraints

[kayloehmann]

Hi,

i have an issue with the following code in TimelineFeed:

	private func addCard(_ card: TimelineCard) {
		self.card = card
        
		card.reload()
		
		card.frame = CGRect(origin: CGPoint(x: 0.0, y: (headerView?.frame.origin.y ?? 0.0) + (headerView?.frame.height ?? 0.0)), size: card.bounds.size)
		
		self.insertSubview(card, at: subviews.count)
        
		let constraints: [NSLayoutConstraint] = [
			NSLayoutConstraint(item: headerView ?? self, attribute: headerView != nil ? .bottom : .top, relatedBy: .equal, toItem: card, attribute: .top, multiplier: 1, constant: 1),
			NSLayoutConstraint(item: self, attribute: .leading, relatedBy: .equal, toItem: card, attribute: .leading, multiplier: 1, constant: 1),
			NSLayoutConstraint(item: self, attribute: .trailing, relatedBy: .equal, toItem: card, attribute: .trailing, multiplier: 1, constant: 1),
			NSLayoutConstraint(item: self, attribute: .bottom, relatedBy: .equal, toItem: card, attribute: .bottom, multiplier: 1, constant: bottomPadding),
			NSLayoutConstraint(item: card, attribute: .height, relatedBy: .equal, toItem: nil, attribute: .notAnAttribute, multiplier: 1, constant: card.bounds.size.height)
		]

		constraints.forEach { $0.isActive = true }
	}

It generates the following error messages:

2021-01-06 18:07:02.636373+0100 EinfachLeichterLeben[20536:946407] [LayoutConstraints] Unable to simultaneously satisfy constraints.
Probably at least one of the constraints in the following list is one you don't want.
Try this:
(1) look at each constraint and try to figure out which you don't expect;
(2) find the code that added the unwanted constraint or constraints and fix it.
(
"<NSLayoutConstraint:0x60000250d630 _TtC20EinfachLeichterLebenP33_CD7A8457D9CF40B1C3DACE082F374E5216TimelineFeedCell:0x7fa758d40cc0'TimelineFeedCell'.top == EinfachLeichterLeben.TimelineCard:0x7fa758d414a0.top + 1 (active)>",
"<NSLayoutConstraint:0x60000250d270 V:[EinfachLeichterLeben.TimelineCard:0x7fa758d414a0]-(20)-| (active, names: '|':_TtC20EinfachLeichterLebenP33_CD7A8457D9CF40B1C3DACE082F374E5216TimelineFeedCell:0x7fa758d40cc0'TimelineFeedCell' )>",
"<NSLayoutConstraint:0x60000250f160 EinfachLeichterLeben.TimelineCard:0x7fa758d414a0.height == 192 (active)>",
"<NSLayoutConstraint:0x600002574870 'UIView-Encapsulated-Layout-Height' _TtC20EinfachLeichterLebenP33_CD7A8457D9CF40B1C3DACE082F374E5216TimelineFeedCell:0x7fa758d40cc0'TimelineFeedCell'.height == 211.333 (active)>"
)

Will attempt to recover by breaking constraint
<NSLayoutConstraint:0x60000250f160 EinfachLeichterLeben.TimelineCard:0x7fa758d414a0.height == 192 (active)>

Make a symbolic breakpoint at UIViewAlertForUnsatisfiableConstraints to catch this in the debugger.
The methods in the UIConstraintBasedLayoutDebugging category on UIView listed in <UIKitCore/UIView.h> may also be helpful.

Latest Xcode, iOS 13 Target

Do you have any ideas, what i could do? It think it also breaks the delegate methods for the header and the card elements.

Thanks! Kay.